Zika and Microcephaly: Report from Brazil

A Brazilian physician-journalist describes the situation

On Jan. 14, the Brazilian Health Ministry released the latest numbers of microcephaly cases possibly linked to Zika virus infection.

A total of 3,530 microcephaly cases suspected to be related to Zika virus are now under investigation, affecting 23 of Brazil's 26 states.

The northeast region of the country has the majority of the cases, with Pernambuco, the first state to detect the problem, showing about 35% of all cases nationally. In an average year, Pernambuco would see no more than a dozen microcephaly cases.

New cases have arisen in the southeast region, in Rio de Janeiro, and in the western state of Mato Grosso. Only Santa Catarina in the south, and Amapá and Acre in the Amazon Basin's far west, have not reported cases of Zika infection or excess numbers of microcephaly.

Also reported recently were results of testing, conducted in collaboration with the U.S. CDC, in four fetal deaths linked to the outbreak. Two of these were spontaneous abortions and two were stillbirths. Investigators found that all four mothers had shown fever and maculopapular rash during pregnancy -- strengthening the still unproven link between Zika virus and the microcephaly cases.

Outbreak History

The first alarm bell rang in Pernambuco and Paraíba, both states of the northeast part of Brazil, in 2014. With 20 microcephaly cases in Pernambuco from January to September that year -- 70% of them only in August and September -- it caught the attention of doctors in neonatal specialty units.

The numbers continued to grow exponentially and in October 2015, the Central Health Ministry decreed a National Public Health Emergency situation. It created a task force and informed the Pan American Health Organization (PAHO) about the problem.

Zika virus was first detected in May of 2015 in Bahia, another northeastern state, and spread rapidly throughout the region. The hypothesis is that Asian soccer fans, who came to watch their teams play in the FIFA World Cup in 2014, brought the virus with them.

Soon after the PAHO communication, French Polynesian authorities also reported that they faced the same problem during a Zika outbreak in 2013 with some microcephaly cases.

Zika Basics

It's a flavivirus first isolated in monkeys in the Zika Forest in Uganda in 1947, and 10 years later in humans in Nigeria. It subsequently became endemic in parts of Africa and Asia. From there the virus has caused outbreaks in the Pacific islands.

The virus is transmitted by Aedes africanus and Aedes aegypti mosquitoes, the latter best known as the vector for yellow fever. These species are now spread worldwide making the threat bigger for other countries.

It generally causes a mild fever and symptoms similar to dengue fever, with red cutaneous maculopapular rash, red eyes, and headache, especially pain behind the eyes and in the joints.

One of the pitfalls of monitoring an outbreak is that many infections can be asymptomatic, making containment more difficult.

Serologic diagnosis is complicated because the PCR test has a very short window of 5 days and is not available everywhere. New tests in urine and more sophisticated blood tests could be useful but availability is restricted in the countries affected by Zika virus.

Link to Microcephaly

Despite the temporal and and geographic correlation between the Zika infections and the staggering number of microcephalic babies, little is known about how that interaction occurs.

An ob-gyn doctor from the state of Paraíba collected amniotic fluid from pregnant mothers who had Zika symptoms and whose babies were born with microcephaly and sent it to virology labs in Rio de Janeiro. Fragments of Zika virus were found in the fluid.

Also, CT scans of the babies with microcephaly showed calcification areas along with the abnormal size of the brains.

Teams are now looking into how the virus affects the central nervous system in its formation and whether there is a most dangerous time during the pregnancy for the infection to cause damage.

It's an ongoing situation and pregnant women throughout the country are understandably anxious. Aedes aegypti is widespread in Brazil's urban areas with high rates of infestation.

Moreover, summer -- and with it, mosquito season -- is here. Cases of Zika infection and dengue will soon reach their annual peaks and won't subside until late May and June.